start_codegen_session · Playwright MCP Server MCP

WHAT IT DOES

What start_codegen_session does on Playwright MCP Server

AI agents invoke start_codegen_session to trigger actions in Playwright MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why start_codegen_session needs a policy

This tool itself doesn't directly execute operations but initializes a session for recording and executing browser automation commands. It falls under Execute rather than Write because Playwright's core capability is to trigger external operations (browser interactions, JavaScript execution) whose effects are determined by the arguments passed to subsequent automation commands.

From the tool's definition Tool is part of Playwright MCP Server that 'Enables browser automation' and allows 'execute JavaScript in a real browser environment.' The start_codegen_session tool initiates a session to 'record Playwright actions,' which sets up infrastructure for…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

start_codegen_session Rate-limited

start_codegen_session stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "start_codegen_session": {
      "limits": [
        {
          "counter": "start_codegen_session_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Playwright MCP Server, so you can run agents against it safely.

FAQ

Questions about start_codegen_session

What does the start_codegen_session tool do? +

Start a new code generation session to record Playwright actions. It is categorised as a Execute tool in the Playwright MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on start_codegen_session? +

Register the Playwright MCP Server MCP server in PolicyLayer and add a rule for start_codegen_session: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Playwright MCP Server. Nothing to install.

What risk level is start_codegen_session? +

start_codegen_session is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit start_codegen_session? +

Yes. Add a rate_limit block to the start_codegen_session rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block start_codegen_session completely? +

Set action: deny in the PolicyLayer policy for start_codegen_session. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides start_codegen_session? +

start_codegen_session is provided by the Playwright MCP Server MCP server (vinothbhc1986/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.